Popular Mechanics crunched the numbers and the dangers of the mercury in a CFL bulb.
While they recommend disposing the bulbs properly , they state:
“Each bulb contains an average
of 5 milligrams of mercury, “which is just enough to cover a ballpoint
pen tip,” says Leslie, associate director of the Lighting Research
Center at Rensselaer. “Though it’s nothing to laugh at, unless you wipe
up mercury [without gloves] and then lick your hand, you’re probably
going to be okay.”